An intracranial hematoma is a collection of blood within the skull. The blood may collect in the brain tissue or underneath the skull, pressing on the brain. It's usually caused by a blood vessel that bursts in the brain. It also may be caused by a head injury due to a car accident or fall.

Some head injuries, such as one that causes only a short period of unconsciousness, can be minor. However, an intracranial hematoma is potentially life-threatening. It usually requires immediate treatment. This might include surgery to remove the blood.


Symptoms of an intracranial hematoma may develop right after a head injury, or they may take weeks or longer to appear. There may be a period of time without symptoms after a head injury. This is called the lucid interval.

Over time, pressure on the brain increases, producing some or all of the following symptoms:

  • Headache that gets worse.
  • Vomiting.
  • Drowsiness and gradual loss of consciousness.
  • Dizziness.
  • Confusion.
  • Pupils that are different sizes.
  • Slurred speech.
  • Loss of movement, known as paralysis, on the opposite side of the body from the head injury.

    As more blood fills the brain or the narrow space between the brain and skull, other symptoms may appear, such as:

    • Feeling very sleepy or sluggish.
    • Seizures.
    • Loss of consciousness.

When to see a doctor

An intracranial hematoma can be life-threatening and needs emergency treatment.

Seek immediate medical attention after a blow to the head if you or someone you know experiences:

  • Loss of consciousness.
  • A headache that doesn't go away.
  • Vomiting, weakness, blurred vision, trouble staying steady.

If you don't notice symptoms right after a hit to the head, watch for physical, mental and emotional changes. For example, if someone seems fine after a head injury and can talk but later becomes unconscious, seek immediate medical care.

And even if you feel fine, ask someone to watch you. Memory loss after a blow to your head can make you forget about the blow. Someone you tell might be more likely to recognize the warning signs and get you medical attention.


The most common cause of an intracranial hematoma is a head injury. A head injury that causes bleeding within the skull may result from motor vehicle or bicycle accidents, falls, assaults, and sports injuries.

If you're an older adult, even mild head trauma can cause a hematoma. This is especially true if you're taking a blood-thinning medicine or an anti-platelet medicine, such as aspirin.

A head injury can cause an intracranial hematoma even if there's no open wound, bruise or other obvious damage.

What happens in the brain to cause bleeding varies based on the type of hematoma. There are three categories of hematoma — subdural hematoma, epidural hematoma and intracerebral hematoma. An intracerebral hematoma also is known as an intraparenchymal hematoma.

Subdural hematoma

A subdural hematoma occurs when blood vessels burst between the brain and the outermost of three protective layers that cover the brain. This outermost layer is called the dura mater. The leaking blood forms a hematoma that presses on brain tissue. A hematoma that gets bigger can cause gradual loss of consciousness and possibly death.

Subdural hematomas can be:

  • Acute. This most dangerous type is generally caused by a bad head injury, and symptoms usually appear immediately.
  • Subacute. Symptoms take time to develop, sometimes days or weeks after a head injury.
  • Chronic. The result of less severe head injuries, this type of hematoma can cause slow bleeding, and symptoms can take weeks and even months to appear. You might not remember hurting your head. For example, bumping your head while getting into the car can cause bleeding, especially if you're on a blood-thinning medicine.

All three types require medical attention as soon as symptoms appear. Prompt medical care may prevent permanent brain damage.

Epidural hematoma

An epidural hematoma occurs when a blood vessel bursts between the outer surface of the dura mater and the skull. Blood then leaks between the dura mater and the skull to form a mass that presses on brain tissue. The most common cause of an epidural hematoma is a head injury. This type also is called an extradural hematoma.

Some people with an epidural hematoma remain conscious. But most become drowsy or go into a coma from the moment of injury. An epidural hematoma that affects an artery in your brain can be deadly without prompt treatment.

Intracerebral hematoma

An intracerebral hematoma occurs when blood pools in the tissues of the brain. An intracerebral hematoma also is called an intraparenchymal hematoma. There are many causes, including:

  • A head injury, which can result in multiple intracerebral hematomas.
  • A rupture of a bulging blood vessel, known as an aneurysm.
  • Poorly connected arteries and veins from birth.
  • High blood pressure.
  • Tumors.
  • Some diseases can cause sudden leakage of blood into the brain.

Risk factors

Intracranial hematomas can be caused by a head injury. Activities that increase the risk of a bad head injury, such as riding a motorcycle or bicycle without a helmet, also raise the risk of an intracranial hematoma.

The risk of a subdural hematoma increases with age. The risk also is greater for people who:

  • Take aspirin or another blood-thinning medicine daily.
  • Have alcohol use disorder.

Some conditions also may increase the risk of having an intracerebral hematoma. They include being born with poorly connected arteries and veins, and having a bulging blood vessel in the brain, known as an aneurysm. High blood pressure, tumors and some diseases also increase the risk.


To prevent or minimize a head injury that may cause an intracranial hematoma:

  • Wear a helmet and make sure your kids wear helmets. Wear an appropriate and properly fitted helmet when doing any activity that could result in head injury. This includes while playing contact sports, bicycling, motorcycling, skiing, horseback riding, skating, skateboarding and snowboarding.
  • Buckle your seat belt and make sure your kids are buckled in. Do so every time you drive or ride in a motor vehicle.
  • Protect young children. Always use properly fitted car seats. Pad countertops and edges of tables, block stairways, and attach heavy furniture or appliances to the wall to prevent tipping. Keep children from climbing on objects that aren't safe or steady. Place safety gates on stairs and guards on windows.

June 08, 2024
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